A 5-day-old male neonate develops progressive lethargy after initiation of protein feeds. By day 5, he is unresponsive with irregular breathing. ABG: pH 7.51, pCO2 20 mmHg (primary respiratory alkalosis). Serum ammonia is 920 μmol/L. Liver enzymes, bilirubin, and glucose are normal. Plasma citrulline is low; urine orotic acid is markedly elevated. What is the most urgent intervention?

Which two veins join to form a brachiocephalic vein?

A 4-year-old boy is referred to genetics for developmental delay, autism spectrum disorder, and multiple congenital anomalies. Physical examination reveals mild dysmorphic facial features, hypotonia, and a ventricular septal defect. There is no significant family history. The geneticist suspects an underlying chromosomal disorder but is concerned that the abnormality may be too small to be identified on a routine karyotype. Which of the following is the most appropriate first-line genetic test?

In humans and many other vertebrates, the midgut contains minute fingerlike projections called _______ that increase the surface area of the gut epithelium.

A 10-year-old is referred for weight gain. Review of his growth chart shows he has gained 9 kg over 18 months but his height has dropped from the 52nd to the 12th percentile over the same period. BMI is at the 97th percentile. BP is 148/90 mmHg. Examination reveals wide violaceous abdominal striae, a dorsocervical fat pad, and proximal muscle weakness (he cannot rise from a chair without using his arms). Which diagnosis best explains this constellation of findings?

A 10-year-old boy is admitted to the pediatric ICU after sustaining multiple abdominal injuries in a motor vehicle collision. Over the past 12 hours, he has received aggressive fluid resuscitation and blood product transfusions. He is mechanically ventilated. The bedside nurse reports increasing ventilator pressures and decreasing urine output. Current findings include: HR: 145 beats/min BP: 88/50 mmHg Peak inspiratory pressures: increasing from 22 to 38 cm H₂O Urine output: 0.2 mL/kg/hr Abdomen: markedly distended and tense Serum lactate: 6.1 mmol/L Bladder pressure measurement is 24 mmHg. Which of the following is the most appropriate next step in management?

A 15-year-old male with no prior GI history presents with severe epigastric pain radiating to the back, nausea, and vomiting after a large meal. Lipase is 1,240 U/L (>3× ULN). Amylase is 890 U/L. Ultrasound shows peripancreatic edema and a 4 mm common bile duct stone. He is hemodynamically stable. What is the most appropriate approach to nutrition in this patient?

A 16-year-old female with known Graves disease, non-adherent to methimazole for 3 months, undergoes emergency appendectomy. Five hours post-operatively, she develops fever of 40.3°C, HR 162 bpm, agitation, tremors, and severe diaphoresis. BP is 178/100 mmHg. Burch-Wartofsky score is 75. Which management sequence is correct for thyroid storm?

A 3-year-old boy is brought to the emergency department for vomiting, lethargy, and abdominal pain. His mother’s boyfriend reports that the child “fell off the couch” earlier that day. On examination, the child is pale and withdrawn. Vital signs are notable for: HR: 155 beats/min BP: 82/44 mmHg RR: 30 breaths/min Physical examination reveals faint bruising over the abdomen and scattered ecchymoses on the back. Abdominal palpation elicits diffuse tenderness and guarding. Laboratory studies show: Hemoglobin: 8.2 g/dL AST: 310 U/L ALT: 275 U/L Lipase: 650 U/L A CT scan of the abdomen demonstrates a pancreatic transection and small amount of free intraperitoneal fluid. Which of the following findings should most strongly increase the clinician’s suspicion for child abuse as the cause of this child’s injuries?

A 15-year-old sustains a gunshot wound to the right lower abdomen. In the trauma bay: HR 108 bpm, BP 112/68 mmHg. Abdominal exam shows peritoneal penetration on local wound exploration. There is no peritonitis on exam. CT abdomen/pelvis shows the trajectory traverses the peritoneal cavity. What is the most appropriate definitive management decision?